This invention relates generally to the generation of intense, high-energy ion pulses and more particularly to the extraction of magnetically compressed ion rings without the use of metallic walls or an external magnetic field to guide the ions.
No means exists for extracting a compressed ion ring and guiding a pulse, for example, to a target, without metallic walls which surround the ion pulse or an external magnetic field. Such requirements are disadvantageous since, for example, in systems which require a large separation between an ion accelerator and the target, neither metallic walls nor an external magnetic field is suitable for guiding an ion beam to the target.
The acceleration of ions by magnetic compression of ion rings has been treated by several authors:
(a) H. H. Fleischmann, Proc. of Electr. and Electromagnetic Conf. of Plasmas, NY (1974); (b) R. N. Sudan and E. Ott, Phys. Rev. Letts. 33, 355 (1974); PA1 (c) E. S. Weibel, Phys. of Fluids 20, 1195 (1977); PA1 (d) R. V. Lovelace, Kinetic Theory of Ion Ring Compression (unpublished); PA1 (e) P. Sprangle and C. A. Kapetanakos, J. Appl. Phys. 49, 1 (1978); and PA1 (f) R. N. Sudan, Phys. Rev. Lett. 41, 476 (1978).
However, with the exception of reference (f), the references have not considered the extraction of the ring after compression. In fact, extraction is irrelevant to references (a) to (d) because their objective is the use of ion rings for the magnetic confinement of plasmas in fusion reactors. Reference (e) discloses the non-adiabatic compression of weak rings. Reference (f) having inertial fusion as its objective, discusses the extraction of the ring after compression. However, in Sudan's scheme, the image currents on the wall of a tube that surrounds the ring provide a radial equilibrium during propagation of the ring from the compression region to the target. The guide tube is destroyed and must be replaced in each shot.